Monitoring condition of electrochemical cells

ABSTRACT

Disclosed herein are methods, systems, and computer programs that relate to monitoring condition of one or more electrochemical cells or a group of the electrochemical cells in one or more electrolyzers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit to U.S. Provisional Patent ApplicationNo. 62/463,124, filed Feb. 24, 2017, which is incorporated herein byreference in its entirety in the present disclosure.

BACKGROUND

Monitoring systems and processes is gaining increasing attention andimportance in both industry and academia. The monitoring ofelectrochemical cells in an electrolyzer may provide accurate andimmediate information on variables that describe the state of a reactionin the process. There is a considerable demand for the monitoring of theelectrochemical cells in an electrolyzer for process development, pilotplant operation, and monitoring of industrial manufacturing processes.

SUMMARY

In one aspect, there is provided a method for monitoring condition ofone or more electrochemical cells in an electrolyzer, the methodcomprising:

characterizing a reference voltage range for one or more electrochemicalcells in an electrolyzer during operation, wherein the one or moreelectrochemical cells comprise an anode in contact with an anolytecomprising metal ions, and wherein the reference voltage range isdynamic dependent on factors comprising current density andconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

acquiring a voltage of the one or more electrochemical cells during theoperation;

comparing the acquired voltage with the reference voltage range based onthe factors; and

generating an alarm trigger when the acquired voltage deviates from thereference voltage range, thereby monitoring the condition of the one ormore electrochemical cells in the electrolyzer.

In some embodiments of the above noted aspect, further comprisingdetermining the concentration of the metal ions in the anolyte of theone or more electrochemical cells and based on the determination,characterizing the reference voltage range for the one or moreelectrochemical cells. In some embodiments of the above noted aspect andembodiments, comprising determining the concentration of the metal ionsin the feed anolyte and/or exit anolyte from the one or more of theelectrochemical cells in the electrolyzer.

In some embodiments of the above noted aspect and embodiments, thecharacterizing the reference voltage range comprises characterizing thereference voltage range versus current distribution and determining theacquired voltage comprises determining the acquired voltage versuscurrent distribution during the operation of the one or moreelectrochemical cells.

In some embodiments of the above noted aspect and embodiments, thefactors further comprise temperature, pressure, flow rate, andcombinations thereof.

In some embodiments of the above noted aspect and embodiments, theanolyte further comprises salt ions and the factors further compriseconcentration of the salt ions in the anolyte during the operation ofthe one or more electrochemical cells. In some embodiments, the saltions are alkali metal salt ions or alkaline earth metal salt ions. Insome embodiments, the salt ions are alkali metal salt ions or alkalineearth metal salt ions and halide ions.

In some embodiments of the above noted aspect and embodiments, theconcentration of the metal ions in the anolyte comprises concentrationof the metal ions in the lower oxidation state, concentration of themetal ions in the higher oxidation state, ratio of the concentration ofthe metal ions in the lower oxidation state to the metal ions in thehigher oxidation state, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the metalion is copper (Cu).

In some embodiments of the above noted aspect and embodiments, theconcentration of the metal ions comprises concentration of Cu(I),concentration of Cu(II), concentration of total Cu(I) and Cu(II), ratioof the concentration of Cu(I) to Cu(II), or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the metalion is in form of a metal halide.

In some embodiments of the above noted aspect and embodiments, themethod further comprises obtaining data from in-situ or ex-situanalytical techniques and based on the data determining theconcentration of the metal ions and/or the concentration of the saltions in the anolyte during the operation. In some embodiments, thein-situ or ex-situ analytical techniques comprise coriolis meter,titration of the anolyte, inductively coupled plasma (ICP) technique,ultra-microelectrode (UME) technique, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, theoperation comprises start-up, shut-down, steady state, transient state,or combinations thereof.

In some embodiments of the above noted aspect and embodiments,generating the alarm trigger comprises generating an alarm to analyzethe one or more electrochemical cells in the electrolyzer; generatinginterlock protocol; generating shut-down protocol; or combinationsthereof.

In some embodiments of the above noted aspect and embodiments, themethod further comprises classifying the one or more electrochemicalcells as significantly damaged, damaged, or undamaged, based on thecomparison or the alarm trigger.

In some embodiments of the above noted aspect and embodiments, themethod further comprises measuring a physical parameter of the one ormore electrochemical cells classified as significantly damaged ordamaged, wherein the physical parameter comprises current distribution,coloration of liquid exiting the cells, pressure of gas in the cells,pressure or flow of liquid entering the cells, pressure or flow ofliquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, themethod further comprises based on the measurement, evaluating: size andposition of a pinhole in a membrane in the cell; position of blockage ofthe flow in the cell; position of a pinch in feed line; fouling of themembrane; construction of the cell; welded points in the cell; orcombinations thereof.

In some embodiments of the above noted aspect and embodiments, themethod further comprises taking a maintenance action on the one or moreelectrochemical cells based on the evaluation.

In one aspect, there is provided a system for monitoring condition ofone or more electrochemical cells in an electrolyzer, the systemcomprising:

a voltage acquisition module coupled to each one of electrochemicalcells or a group of the electrochemical cells in an electrolyzer andadapted for characterizing a reference voltage range and for acquiringvoltage for each one of the electrochemical cells or the group of theelectrochemical cells during operation, wherein each one of theelectrochemical cells comprise an anode in contact with an anolytecomprising metal ions, and wherein the reference voltage range isdynamic dependent on factors comprising current density andconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

a factor acquisition module adapted for acquiring data related to thefactors comprising the current density and the concentration of themetal ions in the anolyte of the one or more electrochemical cells;

a comparison module coupled to the voltage acquisition module and thefactor acquisition module, the comparison module adapted to compare theacquired voltage with the characterized reference voltage range based onthe factors; and trigger an alarm when the acquired voltage deviatesfrom the reference voltage range.

In some embodiments of the above noted aspect, the anolyte furthercomprises salt ions and the factors further comprise concentration ofthe salt ions in the anolyte of the one or more electrochemical cells.

In some embodiments of the above noted aspect and embodiments, thefactor acquisition module is adapted to acquire data related to thefactors comprising the current density, concentration of the metal ionsin the lower oxidation state, concentration of the metal ions in thehigher oxidation state, ratio of the concentration of the metal ions inthe lower oxidation state to the metal ions in the higher oxidationstate, and/or concentration of the salt ions.

In some embodiments of the above noted aspect and embodiments, the metalion is Cu.

In some embodiments of the above noted aspect and embodiments, theoperation comprises start-up, shut-down, steady state, transient state,or combinations thereof.

In some embodiments of the above noted aspect and embodiments, thecomparison module is adapted to trigger the alarm by sound, bygenerating interlock protocol, by generating shut-down protocol, orcombinations thereof. In some embodiments of the above noted aspect andembodiments, the comparison module is further adapted to classify thecells as significantly damaged cells, damaged cells, and undamagedcells, based on the comparison.

In some embodiments of the above noted aspect and embodiments, thesystem further comprises a storage module coupled to the voltageacquisition module; the factor acquisition module; and the comparisonmodule, adapted for storing: the reference voltage range for each one ofthe cells; the acquired voltage for each one of the cells; theconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells; the concentration of the salt ions in the anolyteof the one or more electrochemical cells; current density; and thecomparison data.

In some embodiments of the above noted aspect and embodiments, thevoltage acquisition module comprises a current controlling module, thecurrent controlling module being adapted to control current in each oneof the cells or group of cells at start-up, steady state, shut-down,and/or transient state of the cells.

In some embodiments of the above noted aspect and embodiments, thesystem further comprises a damage evaluation module coupled to thecomparison module, the damage evaluation module adapted to obtaininformation from one or more sensors adapted for measuring a physicalparameter of each one of the cells classified as significantly damagedcells or damaged cells, wherein the physical parameter comprises currentdistribution, coloration of liquid exiting the cells, pressure of gas inthe cells, pressure or flow of liquid entering the cells, pressure orflow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, thedamage evaluation module is adapted for evaluating at least one of aposition and size of a pinhole in a membrane; position of blockage ofthe flow in the cell; position of a pinch in feed line; fouling of themembrane; construction of the cell; welded points in the cell; orcombinations thereof, using the measured physical parameter for each oneof the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, thesystem further comprises an electrolyzer maintenance module coupled tothe damage evaluation module and adapted to transmit a signalrepresentative of a maintenance action to be performed on any one of thesignificantly damaged or damaged cells, the maintenance action beingbased on the evaluation of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, thesensor comprises one of a differential pressure sensor and/or a liquidsensor for measuring a level or flow of liquid in a cell.

In one aspect, there is provided a computer program product encoded on anon-transitory computer-readable medium, which when executed, causes thecomputer to monitor condition of one or more electrochemical cells in anelectrolyzer, which computer program product comprises:

instructions executable to characterize reference voltage range for eachone of electrochemical cells in an electrolyzer during operation,wherein each one of the electrochemical cells comprise an anode incontact with an anolyte comprising metal ions, and wherein the referencevoltage range is dynamic dependent on factors comprising current densityand concentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

instructions executable to acquire voltage for each one ofelectrochemical cells in an electrolyzer during operation;

instructions executable to acquire data related to the factorscomprising the current density and the concentration of the metal ionsin the anolyte during the operation of the one or more electrochemicalcells;

instructions executable to compare the acquired voltage with thecharacterized reference voltage range based on the factors; and

instructions executable to trigger an alarm when the acquired voltagedeviates from the reference voltage range.

In some embodiments of the above noted aspect, the instructionsexecutable to trigger the alarm comprise triggering the alarm,generating interlock protocol, generating shut-down protocol, orcombinations thereof.

In some embodiments of the above noted aspect and embodiment, computerprogram product further comprises, based on the comparison, instructionsexecutable to classify the cells as significantly damaged cells, damagedcells, and undamaged cells.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to storeinformation comprising the reference voltage range for each one of thecells; the acquired voltage for each one of the cells; the concentrationof the metal ions in the anolyte of the one or more electrochemicalcells; the concentration of salt ions in the anolyte of the one or moreelectrochemical cells; current density; and the comparison data.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to obtaininformation from one or more sensors adapted for measuring a physicalparameter of each one of the cells classified as significantly damagedcells or damaged cells, wherein the physical parameter comprises currentdistribution, coloration of liquid exiting the cells, pressure of gas inthe cells, pressure or flow of liquid entering the cells, pressure orflow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to evaluateat least one of a position and size of a pinhole in a membrane; positionof blockage of the flow in the cell; position of a pinch in feed line;fouling of the membrane; construction of the cell; welded points in thecell; or combinations thereof, using the measured physical parameter foreach one of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to transmit asignal representative of a maintenance action to be performed on any oneof the significantly damaged or damaged cells, the maintenance actionbeing based on the evaluation of the significantly damaged or damagedcells.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention may be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is an illustration of some embodiments of the electrochemicalcell in the electrolyzer.

FIG. 2 is an illustration of some embodiments of the monitoring methodsdescribed herein.

FIG. 3 is an illustration of some embodiments of the reference voltagerange and the acquired voltage described herein.

FIG. 4 is an illustration of some embodiments of the monitoring systemsdescribed herein.

FIG. 5 is an illustration of some embodiments described in Example 2herein.

DETAILED DESCRIPTION

Disclosed herein are systems, methods, and computer program productsthat relate to the monitoring of the electrochemical cells in anelectrolyzer system by monitoring the voltage of the electrochemicalcells and its dependence on other factors of the system; to identify thedamaged or underperforming cells; and to provide maintenance to thecells.

Before the present invention is described in greater detail, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only and is not intended to be limiting.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the invention, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Certain ranges that are presented herein with numerical values may beconstrued as “about” numerical. The “about” is to provide literalsupport for the exact number that it precedes, as well as a number thatis near to or approximately the number that the term precedes. Indetermining whether a number is near to or approximately a specificallyrecited number, the near or approximating unrequited number may be anumber, which, in the context in which it is presented, provides thesubstantial equivalent of the specifically recited number.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, representativeillustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The dates of publication provided may bedifferent from the actual publication dates which may need to beindependently confirmed.

It is noted that, as used herein and in the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. It is further noted that the claimsmay be drafted to exclude any optional element. As such, this statementis intended to serve as antecedent basis for use of such exclusiveterminology as “solely,” “only” and the like in connection with therecitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinvention. Any recited method can be carried out in the order of eventsrecited or in any other order which is logically possible.

Methods and Systems

The methods and systems provided herein for the monitoring of theelectrochemical cells in the electrolyzer relate to any electrochemicalcell that comprises metal ions in the anolyte in the anode chamber ofthe cell and where the anode oxidizes the metal ions from loweroxidation state to the higher oxidation state. The methods and systemsprovided herein comprise the detection of cells with damage to theircomponents such as, pinhole in ion exchange membranes, pinched tubes,broken parts, welded joints, etc. and with lower voltage efficiency.With such a diagnosis, better overall electrolysis efficiency of theelectrolyzer can be achieved throughrearranging/replacement/decommissioning of the damaged cells in theelectrolyzer.

Illustrated in FIG. 1 is an example of an electrochemical cell 100 inthe electrolyzer, as monitored by the methods and systems providedherein. The “cell” includes the smallest group of anodes and cathodesthat are connected to the same current feeder. The ways the anodes,cathodes and membrane are connected differ according to the selectedtechnology. For example, the electrodes can be connected in parallel, inseries, or a combination thereof. For example, a bipolar electrolyzerhas a plurality of cells.

The electrolyzer may have any number of the electrochemical cells andthere may be any number of the electrolyzers in a plant. There is ananode in contact with an anode electrolyte or anolyte in an anodechamber and a cathode in contact with a cathode electrolyte or catholytein a cathode chamber, in the electrochemical cell provided herein. Theanode and the cathode may be separated by one or more ion exchangemembranes (IEM). The IEM may be an anion exchange membrane (AEM), acation exchange membrane (CEM), or both. In some embodiments, where boththe AEM and the CEM are present, a middle chamber is formed between theAEM and the CEM that comprises an electrolyte. The electrochemical cellcomprises an anode in contact with an anode electrolyte wherein theanode electrolyte comprises metal ions in an aqueous medium such as saltwater; a cathode in contact with a cathode electrolyte; and a currentsource configured to apply current to the anode and the cathode whereinthe anode is configured to oxidize the metal ion from a lower oxidationstate to a higher oxidation state.

The anode chamber of the electrochemical cell illustrated in FIG. 1 hasanode that, on the application of current at the anode and the cathode,oxidizes metal ions from the lower oxidation state to the higheroxidation state. The process has been described in detail in U.S. Pat.No. 9,187,834, issued Nov. 17, 2015; U.S. Pat. No. 9,200,375, issuedDec. 1, 2015; and U.S. patent application Ser. No. 14/446,791, filedJul. 30, 2014, all of which are incorporated herein by reference intheir entireties in this application.

The anode or the anolyte comprises metal ions (illustrated as M inFIG. 1) which are oxidized at the anode from lower oxidation stateM^(L+) to the higher oxidation state M^(H+). For example only, in theelectrochemical cell oxidation of metal ions, such as, metal halidesfrom a lower oxidation state to a higher oxidation state occurs in theanode chamber of the electrochemical cell. In some embodiments, theanolyte further comprises salt ions in water. The salt ions comprisealkali metal ions such as, for example only, alkali metal halide oralkaline earth metal ions such as, for example only, alkaline earthmetal halide. Examples of salts include, without limitation, potassiumchloride or sodium chloride or lithium chloride or magnesium chloride orcalcium chloride or strontium chloride or ammonium chloride, or sulfateequivalents of these salts, and the like. Other salts of the alkalimetal ions or alkaline earth metal ions are well within the scope of theinvention. The salt ions may also be present in the catholyte.Therefore, this salt solution can be used as an anode electrolyte,cathode electrolyte, and/or brine in the middle compartment.Accordingly, to the extent that such equivalents are based on orsuggested by the present system and method, these equivalents are withinthe scope of the description.

In such electrochemical cells, cathode reaction may be any reaction thatdoes or does not form an alkali in the cathode chamber. Such cathodeconsumes electrons and carries out any reaction including, but notlimited to, the reaction of water to form hydroxide ions and hydrogengas; or reaction of oxygen gas and water to form hydroxide ions; orreduction of protons from an acid such as hydrochloric acid to formhydrogen gas; or reaction of protons from hydrochloric acid and oxygengas to form water, etc.

As used herein, the current includes current applied to or drawn from anelectrochemical cell that drives a desired reaction between the anodeand the cathode in the electrochemical cell. Once the cell reaches acertain voltage based on the voltage of the reactions and resistiveloses, the voltage is acquired during operation in accordance withmethods and systems provided herein. In the electrochemical cellillustrated in FIG. 1, the desired reaction is the oxidation of themetal ions from the lower oxidation state to the higher oxidation state.The current may be applied to the electrochemical cell by any means forapplying the current across the anode and the cathode of theelectrochemical cell. Such means are well known in the art and include,without limitation, devices, such as, electrical power source, fuelcell, device powered by sun light, device powered by wind, andcombinations thereof.

The voltage of the electrochemical cell at which the desired reactiontakes place may be dependent on several factors, including but notlimited to, current density, concentration of the metal ions in theanolyte, concentration of the salt ions in the anolyte, amount of waterin the anolyte and catholyte, ratio of the metal ions concentration inthe lower oxidation state to the metal ion concentration in the higheroxidation state in the anolyte, temperature, pressure, differentialpressure, pH, flow rate, etc. The voltage may also vary depending on thestages of the operation such as start-up, shut-down, transient state, orsteady state, etc. Any number of problems may occur in theelectrochemical cells during operation which may result ininefficiencies and damage of the electrochemical cells. It may bechallenging to devise a method to monitor the conditions of theelectrochemical cells during operation due to several parameters of theelectrochemical process. Applicants have devised a uniquemethod/system/computer program product to monitor the condition of theelectrochemical cells by monitoring the voltage as well as its dynamicdependence on the concentration of the metal ions in the anolyte andoptionally other factors, in the electrochemical cells.

In one aspect, there is provided a method for monitoring condition ofone or more electrochemical cells in an electrolyzer, the methodcomprising:

characterizing a reference voltage range for one or more electrochemicalcells in an electrolyzer during operation, wherein the one or moreelectrochemical cells comprise an anode in contact with an anolytecomprising metal ions, and wherein the reference voltage range isdynamic dependent on factors comprising current density andconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

acquiring a voltage of the one or more electrochemical cells during theoperation;

comparing the acquired voltage with the reference voltage range based onthe factors; and

generating an alarm trigger when the acquired voltage deviates from thereference voltage range, thereby monitoring the condition of the one ormore electrochemical cells in the electrolyzer.

In some embodiments, the systems and methods provided herein formonitoring the condition of the one or more electrochemical cells in theelectrolyzer relate to an on-line and real time monitoring of the cells.The on-line monitoring includes real time retrieval and analysis of datarelated to a process/system and dynamic control of the process/system toensure desired operation. The on-line monitoring can supply processinformation in real time that enables efficient monitoring and controlof the cells. While the on-line monitoring method/system may be fully orpartially automated, the method/system may involve off-line techniqueswhere the sample may be transported to a remote or centralizedlaboratory for analysis. In some embodiments of the methods and systemsprovided herein, the on-line monitoring method/system is fullyautomated. In some embodiments of the methods and systems providedherein, the on-line monitoring method/system is partially automated.

FIG. 2 illustrates some of the steps of the methods as provided herein.It is to be understood that the order of the steps may be changed andone or more steps may be omitted depending upon the desired process.

The methods provided herein comprise characterizing the referencevoltage range for the one or more electrochemical cells in theelectrolyzer during the operation (step II in FIG. 2), wherein thereference voltage range is dynamic dependent on factors comprisingcurrent density and concentration of the metal ions in the anolyte ofthe one or more electrochemical cells. The methods provided hereinfurther comprise determining the concentration of the metal ions in theanolyte of the one or more electrochemical cells and based on thedetermination, characterizing the reference voltage range for the one ormore electrochemical cells (step I in FIG. 2). The steps I and II mayinterchange in order or may be simultaneous. In some embodiments, thestep of determining the concentration of the metal ions in the anolyteof the one or more electrochemical cells may be simultaneous with a stepof determining the current density of the cell. In some embodiments,characterizing the reference voltage range comprises characterizing thereference voltage range versus current distribution. The “referencevoltage range” as used herein is a voltage range for an optimumefficiency of the operation of the one or more electrochemical cells.The reference voltage range of the electrochemical cell provided hereinis dynamic or changing based on the current density as well as theconcentration of the metal ions in the anolyte. For example, thereference voltage range is dynamically dependent on the concentration ofthe metal ions in the feed anolyte and/or exit anolyte from the one ormore of the electrochemical cells in the electrolyzer.

For example, during operation, the anolyte with a certain concentrationof the metal ions is fed to the anode chamber or exits the anodechamber. The exiting anolyte from the anode chamber may be used in otherorganic reactions where the metal ions may get reduced and the remainingmetal ion solution is recirculated back to the anode chamber. Variousorganic reactions are known and an example of halogenation reactionusing the metal ions has been described in U.S. Pat. No. 9,187,834,issued Nov. 17, 2015, which has been incorporated herein by reference inits entirety. Therefore, the concentration of the metal ions enteringthe anode chamber (after participating in other organic reactions) andthe concentration of the metal ions exiting the anode chamber (afteroxidation of the metal ions at the anode in the electrochemical cell)are constantly in flux. Depending on the rate of reactions and theprocess parameters, such as temperature, pressure, flow rates, watercontent, etc. there may be a change in the concentration of the metalions in the feeding and exiting anolyte compositions. The methods andsystems provided herein characterize the reference voltage range basedon its dynamic dependence on the concentration of the metal ions. Ifthere is any damage to the electrochemical cell (as described herein),there may be a change in the concentration of the metal ions which wouldaffect the voltage of the cell. The deviation of the voltage from thereference voltage range may be then used to monitor the condition of thecells.

The concentration of the metal ions may be determined based on variousin-situ or ex-situ analytical techniques described herein. The dataobtained from the analytical techniques is used to determine theconcentration of the metal ions in the anolyte being fed into the anodechamber or the anolyte exiting the anode chamber after the oxidation ofthe metal ions from the lower oxidation state to the higher oxidationstate. The concentration of the metal ions include, without limitation,the concentration of the metal ions in the lower oxidation state,concentration of the metal ions in the higher oxidation state, ratio ofthe concentration of the metal ions in the lower oxidation state to themetal ions in the higher oxidation state, or combinations thereof. Basedon the concentration of the metal ions (and the current density), thereference voltage range is characterized.

The methods provided herein further comprise acquiring a voltage of theone or more electrochemical cells during the operation (step III in FIG.2). The “acquired voltage” as used herein is the voltage during theoperation of the one or more electrochemical cells.

The methods provided herein further comprise comparing the acquiredvoltage with the reference voltage range based on the factors (step IVin FIG. 2). Based on the comparison, the methods further comprisegenerating an alarm trigger when the acquired voltage deviates from thereference voltage range (step V in FIG. 2). In some embodiments, thegenerating the alarm trigger comprises generating an alarm to analyzethe one or more electrochemical cells in the electrolyzer; generatinginterlock protocol; generating shut-down protocol; or combinationsthereof.

In the aspects and embodiments provided herein, the operation comprisesstart-up, shut-down, steady state, transient state, or combinationsthereof. During the transient state of the operation, different currentdensities are applied from standard due to energy price fluctuations ormarket demands which would drive load shedding (reducing current densityto lower production rates) or load increasing (increasing currentdensity to increase production rates). The load shedding or loadincreasing may also be timed with respect to the time of the day. Forexample, load increasing in the night and load shedding in the day timeto reduce energy costs.

FIG. 3 illustrates some embodiments of the methods and systems relatedto the comparison of the acquired voltage with the reference voltagerange based on the factors. Solid line illustrates reference cell (orgroup of cell) voltage and upper and lower bounds indicate the referencevoltage range. The reference voltage range is characterized depending onthe anolyte composition such as, but not limited to, the concentrationof the metal ions. The acquired voltage falling above or below thisrange would result in generating an alarm trigger and/or interlockprotocol and/or shut-down protocol.

For example during the start-up of the cell or a group of cells in theelectrolyzer, the cell currents are typically ramped up slowly (linearlyor in steps) and the reference voltage range for specific anolytecompositions (e.g. concentrations of the metal ions) is characterizedand used as reference within the system. In some embodiments, if duringthe start-up the acquired voltage deviates outside the reference voltagerange an alarm may be triggered or the interlock protocol may begenerated and the start-up may be changed or stopped, based onprescribed interlock controls.

As with start-up conditions, during steady state also the referencevoltage range is characterized dependent on the anolyte composition(e.g. concentrations of the metal ions). In some embodiments, the timescales with voltage deviation (voltage deviation over time) may belonger depending on the problem in the cell which is measured andevaluated, as described below. In some embodiments, when the alarm istriggered, the operator may inspect the cell or group of cells manuallyin detail. In some embodiments, the methods and systems provided hereinconduct an automated check of the physical parameters to check theconditions of the cells. In some embodiments, the voltage deviation mayhave shorter timescales and may signify something catastrophic happeningwith the cells in the period of seconds/minutes/hours. In thiscondition, the system may generate an alarm as well as initiateinterlocks and shut-down protocols.

As explained herein, in the methods and systems provided herein, theanode is in contact with the anolyte comprising metal ions and thereference voltage range is dynamic dependent on the concentration of themetal ions in the anolyte of the one or more electrochemical cells. The“metal ion” or “metal” or as used herein, includes any metal ion capableof being converted from lower oxidation state to higher oxidation state.The metal ions may be in the form of any compound, for example only,metal halide, metal sulfate, etc. Examples of metal ions include, butnot limited to, iron, chromium, copper, tin, silver, cobalt, uranium,lead, mercury, vanadium, bismuth, titanium, ruthenium, osmium, europium,zinc, cadmium, gold, nickel, palladium, platinum, rhodium, iridium,manganese, technetium, rhenium, molybdenum, tungsten, niobium, tantalum,zirconium, hafnium, and combination thereof. The “oxidation state” asused herein, includes degree of oxidation of an atom in a substance. Forexample, in some embodiments, the oxidation state is the net charge onthe ion.

In some embodiments, the reference voltage range is dependent on theanolyte composition comprising the concentration of the metal ion in thelower oxidation state and the concentration of the metal ion in thehigher oxidation state.

In some embodiments, the reference voltage range may also be dependenton the anolyte composition comprising the concentrations of the halideions in combination with the concentration of the metal ions. In someembodiments, the reference voltage range may be dependent on the anolytecomposition comprising the concentrations of the metal halide with metalion in both lower as well as higher oxidation state.

In the embodiments of the methods and systems aspects provided herein,when the current is applied to the anode and the cathode of theelectrochemical cells, the anode oxidizes metal ions from loweroxidation state to the higher oxidation state. Therefore, the anolytecomprises metal ions in the lower oxidation state as well as the samemetal ions in the higher oxidation state. The concentration of the metalions in different oxidation states changes in the anolyte as the anodeoxidizes the metal ions. Accordingly, the reference voltage rangedependent on the concentration of the metal ions in the anolyte exitingthe anode chamber, is also dynamic.

In some embodiments of the methods and systems provided herein, theconcentration of the metal ions in the anolyte comprises concentrationof the metal ions in the lower oxidation state, concentration of themetal ions in the higher oxidation state, ratio of the concentration ofthe metal ions in the lower oxidation state to the metal ions in thehigher oxidation state, or combinations thereof.

In some embodiments of the methods and systems provided herein, themetal ion is copper (Cu), iron (Fe), tin (Sn), or Nickel (Ni). In someembodiments of the methods and systems provided herein, the metal ion iscopper (Cu). In some embodiments of the methods and systems providedherein, the metal ion is copper (Cu) in the form of metal compoundcopper chloride (CuCl and CuCl₂). In some embodiments of the methods andsystems provided herein, the concentration of the metal ions comprisesconcentration of Cu(I), concentration of Cu(II), concentration of totalCu(I) and Cu(II), ratio of the concentration of Cu(I) to Cu(II), orcombinations thereof. In some embodiments of the methods and systemsprovided herein, the concentration of the metal ions comprisesconcentration of CuCl, concentration of CuCl₂, concentration of totalCuCl and CuCl₂, ratio of the concentration of CuCl to CuCl₂, orcombinations thereof.

In some embodiments, the anolyte comprising metal ions further comprisessalt ions. In some embodiments, the anolyte comprises metal ions, suchas e.g. metal halide or metal sulfate in salt water. The metal ion maybe present in any compound form such as metal halide, metal sulfate orany suitable metal compound. The salt ions may be any suitable saltincluding but not limited to, alkali metal ion, e.g. alkali metal halideor sulfate; or alkaline earth metal ion, e.g. alkaline earth metalhalide or sulfate. Examples include, without limitation, salts oflithium, sodium, potassium, rubidium, caesium, francium, beryllium,magnesium, calcium, strontium, barium, and the like. The anion in thesalt may be a halide (chloro, bromo, iodo, or fluoro), sulfate or anyother suitable anion. Examples include without limitation, lithiumchloride, sodium chloride, potassium chloride, magnesium chloride,calcium chloride, strontium chloride, etc.

In some embodiments, the reference voltage range is dynamic dependent onfactors comprising the current density, the concentration of the metalions, and the concentration of the salt ions. In some embodiments, thesalt ions comprise salt cations as well as salt anions. In someembodiments, the salt ions comprise alkali metal ions and halide ions.In some embodiments, the salt ions comprise alkaline earth metal ionsand halide ions. In some embodiments where the metal ion is metal halideand salt is alkali metal halide, the reference voltage range is dynamicdependent on the concentration of the metal ions, the concentration ofthe alkali metal ions, and concentration of the halide ions. In someembodiments where the metal ion is metal halide and salt is alkalineearth metal halide, the reference voltage range is dynamic dependent onthe concentration of the metal ions, the concentration of the alkalineearth metal ions, and concentration of the halide ions.

In some embodiments, the methods comprise obtaining data from in-situ orex-situ analytical techniques to determine anolyte composition (step Iin FIG. 2). The anolyte composition comprises concentrations of the ionsin the composition. The ions include metal ions and optionally saltions. In some embodiments, the methods provided herein compriseobtaining data from in-situ or ex-situ analytical techniques and basedon the data determining the concentration of the metal ions and/or theconcentration of the salt ions in the anolyte during the operation. Thein-situ or ex-situ analytical techniques include, but not limited to,coriolis meter, titration of the anolyte, inductively coupled plasma(ICP) technique, ultra-microelectrode (UME) technique, or combinationsthereof. Many other in-situ or ex-situ analytical techniques have beendescribed herein and are well known commercially.

Other factors that may affect the reference voltage range includetemperature, pressure, flow of liquid in the cells, or combinationsthereof. In some embodiments of the aforementioned aspects andembodiments, the temperature may be the temperature in any component ofthe process. For example, the temperature can be of the liquid streamsin the electrochemical cell, of the gaseous products/byproducts, of thecomponents of the process such as valves, pumps, compressors, etc. Insome embodiments of the aforementioned aspects and embodiments, thepressure is the gauge pressure in any component of the process. Forexample, the pressure in the electrochemical cell and/or the pressure inthe components of the process such as valves, pumps, compressors, etc.For example only, the pressure gauge may help in determining thedifferential pressure i.e. the pressure drop across the cells and/or tomeasure liquid flow in the cells. In some embodiments of theaforementioned aspects and embodiments, the flow may be the flow ofdifferent liquids or fluids in the tanks, vessels, conduits, pipes, etc.In some embodiments of the aforementioned aspects and embodiments, thedensity, concentration, flow rate, etc. can be of fluids and gases inand out of the electrochemical cell and/or fluids and gases flowingthrough the conduits.

As illustrated in FIG. 2, the methods provided herein further compriseclassifying the one or more electrochemical cells as significantlydamaged, damaged, or undamaged, based on the comparison or the alarmtrigger (step VI in FIG. 2). If the acquired voltage of the cell iswithin the reference voltage range, the cells is considered undamaged.If the acquired voltage of the cell is outside of the reference voltagerange by a small margin (is either higher than the upper range of thereference voltage range or lower than the lower range of the referencevoltage range), the cell is considered damaged and the alarm trigger isgenerated prompting an inspection of the cell. If the acquired voltageof the cell is significantly outside of the reference voltage range, thecell is considered significantly damaged and the alarm trigger isgenerated also generating interlock and shut-down procedure. Thesignificantly damaged cell may be deactivated, removed, replaced, oraccessed for maintenance depending on the condition of the cell.

In some embodiments, the methods provided herein further comprisemeasuring or checking some physical parameters of the significantlydamaged or damaged cells in order to determine the reason for theanomaly in the factors, such as concentration, temperature, pressure,etc. further affecting the voltage of the cells (step VII in FIG. 2).The physical parameters comprises current distribution, coloration ofliquid exiting the cells, pressure of gas in the cells, pressure or flowof liquid entering the cells, pressure or flow of liquid exiting thecells, or combinations thereof. There may be several other physicalparameters that can be measured and evaluated, all of which are withinthe scope of this application. The physical parameters may be measuredmanually, digitally, and/or automatically.

In some embodiments, the methods provided herein further compriseevaluating the components of the cells if an anomaly is detected in themeasurement of the physical parameter (also step VII in FIG. 2). Theevaluation includes evaluating various components of the cellsincluding, but not limited to: membrane in the cell to locate size andposition of a potential pinhole; position of blockage of the flow in thecell; position of a pinch in feed line; fouling of the membrane;construction of the cell to locate leaks or warping if any; weldedpoints in the cell to locate poor electrical distribution; orcombinations thereof. The evaluation may also be conducted manually,digitally, and/or automatically.

The occurrence of holes or tears in the cell membrane also calledpinholes can cause damage to the cell dropping the cell efficiency. Somereasons for the presence of pinholes and pores in the cell membrane arethe formation of voids, blisters, and delaminating of the membrane dueto faults in start-ups and shut-downs and by contaminated electrolytes.The presence of pinholes in the membrane, for example, can affect thecell's efficiency in different ways depending on the pinhole(s)'s sizeand location, as well as the age of the cell.

In some embodiments, the methods provided herein further comprise takinga maintenance action on the one or more electrochemical cells based onthe evaluation (step VIII in FIG. 2).

In some embodiments of the aforementioned aspects and embodiments, themonitoring of the cells in the electrolyzer is fully automated. In someembodiments of the aforementioned aspects and embodiments, themonitoring is partially automated. In some embodiments of theaforementioned aspects and embodiments, the whole monitoring is fullyautomated except for the step of measuring physical parameters andevaluating the components of the cell where the method may be manual,digital, or automated depending on the parameter to be adjusted.

For example, instruction to take maintenance action may be sentmanually, digitally, or automatically to one or more valves to adjustthe flow of the streams, one or more pumps, one or more compressors, oneor more heat exchange units, current controller, and/or one or moreheaters or coolers to turn-on/off or open/close to increase or decreasethe temperature or pressure value of the process. In some embodiments ofthe aforementioned aspects and embodiments, the instructions may be sentto a specific location of the one or more components in order toselectively increase or decrease the flow of liquids (to cause changesin the concentration of the ions in the anolyte), the current density,the temperature and/or pressure value at that specific location.

In one aspect, there is provided a system for monitoring condition ofone or more electrochemical cells in an electrolyzer, the systemcomprising:

a voltage acquisition module coupled to each one of electrochemicalcells or a group of the electrochemical cells in an electrolyzer andadapted for characterizing a reference voltage range and for acquiringvoltage for each one of the electrochemical cells or the group of theelectrochemical cells during operation, wherein each one of theelectrochemical cells comprise an anode in contact with an anolytecomprising metal ions, and wherein the reference voltage range isdynamic dependent on factors comprising current density andconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

a factor acquisition module adapted for acquiring data related to thefactors comprising the current density and the concentration of themetal ions in the anolyte of the one or more electrochemical cells;

a comparison module coupled to the voltage acquisition module and thefactor acquisition module, the comparison module adapted to compare theacquired voltage with the characterized reference voltage range based onthe factors; and trigger an alarm when the acquired voltage deviatesfrom the reference voltage range.

FIG. 4 illustrates a system 200, for monitoring the condition of one ormore electrochemical cells in the electrolyzer, operably connected tothe one or more electrochemical cells. The system 200 of FIG. 4 thatconducts monitoring of the system 100 of FIG. 1 is described in detailbelow.

The system 200 may include a computer interface (where monitoring iscomputer-assisted or is entirely controlled by computer) configured toprovide a user with input and output parameters or is automated tocontrol the conditions of the cells, as described above.

In some embodiments of the aforementioned aspect, the system comprisesthe voltage acquisition module A (as shown in FIG. 4) coupled to eachone of the electrochemical cells or the group of the electrochemicalcells in the electrolyzer and adapted for characterizing the referencevoltage range and for acquiring voltage for each one of theelectrochemical cells or the group of electrochemical cells duringoperation.

In some embodiments of the aforementioned aspect and embodiments, thevoltage acquisition module comprises a current controlling module, thecurrent controlling module being adapted to control current in each oneof the cells or group of cells at start-up, steady state, shut-down,and/or transient state of the cells. In some embodiments, the currentcontrolling module can be used to vary the current density passing inthe cell so as to increase the current supplied to a cell from zero andup to a given optimum value at start-up, or back to zero for a shut-downoperation.

For example, in some embodiments, the electrolyzer is arranged with anumber of cell groupings; each cell grouping may contain any number ofelectrochemicals cells. Each cell voltage may be measured by a metalwire. The wires may be concentrated in a multi-cable protected cablethrough a TFP (Terminal Fuse Protection) device. The voltage acquisitionmodule can thus be used to acquire data from various cell groupings inelectrolyzers. For example, the voltage acquisition module can multiplexthe signals from each cell grouping by a series of relays, in a sequencefor transmission to a personal computer optionally connected in a localnetwork, and in accordance with a given communication setup.

In some embodiments of the aforementioned aspect and embodiments, thesystem further comprises the factor acquisition module B (as shown inFIG. 4) adapted for acquiring data related to the factors comprising thecurrent density and the concentration of the metal ions in the anolyteof the one or more electrochemical cells. In some embodiments, thevoltage acquisition module is adapted for receiving data from the factoracquisition module and based on the data related to the factors,characterizing the reference voltage range. The voltage acquisitionmodule is also adapted for acquiring the voltage of each one of theelectrochemical cells or the group of the electrochemical cells duringoperation.

In some embodiments, the anolyte further comprises salt ions and thefactors further comprise concentration of the salt ions in the anolyteof the one or more electrochemical cells. In some embodiments, thefactor acquisition module is adapted to acquire data related to thefactors comprising the current density, concentration of the metal ionsin the lower oxidation state, concentration of the metal ions in thehigher oxidation state, ratio of the concentration of the metal ions inthe lower oxidation state to the metal ions in the higher oxidationstate, and/or concentration of the salt ions. In some embodiments, thefactor acquisition module is adapted to acquire data from in-situ orex-situ analytical techniques selected from the group consisting oftemperature probe (resistance temperature detectors, thermocouples, gasthermometers, thermistors, pyrometers, infrared radiation sensors,etc.), pressure probe (e.g., electromagnetic pressure sensors,potentiometric pressure sensors, etc.), oxidation-reduction potential(ORP) probe, quadruple mass spectrometer (QMS), ATR probe,ultramicroelectrode (UME) probe, gas chromatography (GC), titrator,inductively coupled plasma (ICP) emission spectrometers, electrochemicalsensor, volatile organic compound (VOC) sensor, coriolis flow meter,volume probes (e.g., geophysical diffraction tomography, X-raytomography, hydroacoustic surveyers, etc.), and other devices fordetermining anolyte composition or the exiting gas composition, e.g.,infrared (IR) spectrometer, nuclear magnetic resonance (NMR)spectrometer, ultraviolet (UV)-vis spectrophotometer, high performanceliquid chromatographs, inductively coupled plasma mass spectrometers,ion chromatographs, X-ray diffractometers, gas chromatographs, gaschromatography-mass spectrometers, flow-injection analysis,scintillation counters, acidimetric titration, and flame emissionspectrometers, etc. It is to be understood that there can be otheranalytical techniques from where the data can be retrieved and as suchall such techniques are within the scope of this disclosure. The one ormore analytical techniques are configured for monitoring theconcentration of the metal ions and/or salt ions in the anolyte.

In some embodiments, the one or more analytical techniques individuallymay also have a computer interface configured to provide a user with thecollected data about the anolyte composition, current density,temperature, pressure etc. For example, the analytical techniques maydetermine the concentration of the metal ions and/or the salt ions inthe anolyte and the computer interface may provide a summary of thechanges in the composition within the aqueous anolyte over time. In someembodiments, the summary may be sent to the system as factor acquisitiondata or is stored as a computer readable data file or may be printed outas a user readable document. In some embodiments, the summary may besent to the voltage acquisition module to compute and characterize thereference voltage range.

Similarly, the collective data in the system obtained by the voltageacquisition module and the factor acquisition module may be stored as acomputer readable data file or may be printed out as a user readabledocument.

In some embodiments, the one or more analytical techniques may beconfigured to determine the parameters of the process, such as,concentration of the metal ions and/or the salt ions at regularintervals, e.g., determining the composition every 1 minute, every 5minutes, every 10 minutes, every 30 minutes, every 60 minutes, every 100minutes, every 200 minutes, every 500 minutes, or some other interval.The data retrieved by the factor acquisition module from the one or moreanalytical techniques may be further processed in the system.

In some embodiments, the system further comprises a computing modulewithin the voltage acquisition module configured to characterize thereference voltage range by computing the data received regarding theconcentration of the metal ions in the anolyte from the factoracquisition module.

In some embodiments of the aforementioned aspects and embodiments, thesystem further comprises the comparison module C (as shown in FIG. 4)coupled to the voltage acquisition module and the factor acquisitionmodule, the comparison module adapted to compare the acquired voltagewith the characterized reference voltage range.

In some embodiments of the aforementioned aspects and embodiments, thecomparison module is adapted to trigger the alarm, by generatinginterlock protocol, by generating shut-down protocol, or combinationsthereof. The alarm may not be audible and may be detection of an anomalyfollowed by interlock and/or shut down procedures. Or in someembodiments, the alarm may be an audible sound such as a beep, flash,ring, bell, or the like. After the signal is heard from the system, theuser may manually adjust the parameters or the system may sendinstructions to one or more components to shut-down.

In some embodiments of the aforementioned aspects and embodiments, thecomparison module is further adapted to classify the cells assignificantly damaged cells, damaged cells, and undamaged cells, basedon the comparison.

In some embodiments of the aforementioned aspects and embodiments, thesystem further comprises a storage module (not shown in FIG. 4) coupledto the voltage acquisition module; the factor acquisition module; andthe comparison module, adapted for storing: the reference voltage rangefor each one of the cells; the acquired voltage for each one of thecells; the concentration of the metal ions in the anolyte of the one ormore electrochemical cells; the concentration of the salt ions in theanolyte of the one or more electrochemical cells; current density; andthe comparison data.

In some embodiments of the aforementioned aspects and embodiments, thesystem further comprises a damage evaluation module D (as shown in FIG.4) coupled to the comparison module, the damage evaluation module isadapted to obtain information from one or more sensors adapted formeasuring a physical parameter of each one of the cells classified assignificantly damaged cells or damaged cells, wherein the physicalparameter comprises current distribution, coloration of liquid exitingthe cells, pressure of gas in the cells, pressure or flow of liquidentering the cells, pressure or flow of liquid exiting the cells, orcombinations thereof. In some embodiments, the sensor comprises one of adifferential pressure sensor and/or a liquid sensor for measuring alevel or flow of liquid in a cell.

In some embodiments, the sensors and the analytical techniques describedabove may overlap. In some embodiments, the damage evaluation module maybe coupled also to the factor acquisition module and may receive datarelated to one or more factors to measure the physical parameters.

In some embodiments of the aforementioned aspects and embodiments, thedamage evaluation module D is further adapted for evaluating the causeof the damage to the cells based on the measurement of the physicalparameters. The damage evaluation module D is adapted for evaluating atleast one of a position and size of a pinhole in a membrane; position ofblockage of the flow in the cell; position of a pinch in feed line;fouling of the membrane; construction of the cell; welded points in thecell; or combinations thereof, using the measured physical parameter foreach one of the significantly damaged or damaged cells.

In some embodiments of the aforementioned aspects and embodiments, thesystem further comprises an electrolyzer maintenance module E (as shownin FIG. 4) coupled to the damage evaluation module and adapted totransmit a signal representative of a maintenance action to be performedon any one of the significantly damaged or damaged cells, themaintenance action being based on the evaluation of the significantlydamaged or damaged cells. The maintenance module may operate manually,digitally, or automatically.

In some embodiments of the aforementioned aspects and embodiments, themaintenance module is configured to send instructions to one or more ofthe components of the damaged cell to adjust the flow rate, currentdensity, and/or temperature/pressure such that the concentration of themetal ions is adjusted, thereby adjusting the acquired voltage to alignwith the reference voltage range. The one or more components areselected from, for example only, one or more valves, one or more pumps,one or more compressors, one or more heat exchange units, one or moreheaters or coolers, power source, rectifier, one or more tanks, andcombinations thereof.

In some embodiments, the system may be a computer interface which isconfigured to provide a user with the collected data about the processand systems 100. One or more of the modules of the system may be part ofone or several systems connected to each other. In some embodiments, allof the modules are part of a single computer program encoded to carryout the monitoring of the condition of the electrochemical cells in theelectrolyzer.

In some embodiments, the system may be a computer interface thatprovides a summary of the conditions of the process to the user overtime. In some embodiments, the summary is stored as a computer readabledata file or may be printed out as a user readable document. In someembodiments, the system comprises a monitor screen to display thereference voltage range, acquired voltage, comparison of the referencevoltage range with the acquired voltage, data related to the one or morefactors, combinations thereof. In some embodiments, the system comprisesa monitor screen that displays the aforementioned one or more componentsof the system with respect to their location in the cell system; the oneor more analytical techniques operating in the cell system; and/or thevalues of the one or more factors and/or physical parameters withrespect to their location in the system. In some embodiments of theaforementioned aspects and embodiments, the system has a monitor screenwith a touch screen. The system may be connected to the one or morecomponents as well as the one or more analytical techniques of the cellsystem through wires or wirelessly.

Computer Program Product

In one aspect, there is provided a computer program product encoded on anon-transitory computer-readable medium, which when executed, causes thecomputer to monitor condition of one or more electrochemical cells in anelectrolyzer, in accordance with the methods and systems describedherein.

In one aspect, the computer program product encoded on a non-transitorycomputer-readable medium, which when executed, causes the computer tomonitor condition of one or more electrochemical cells in anelectrolyzer, comprises:

instructions executable to characterize reference voltage range for eachone of electrochemical cells in an electrolyzer during operation,wherein each one of the electrochemical cells comprise an anode incontact with an anolyte comprising metal ions, and wherein the referencevoltage range is dynamic dependent on factors comprising current densityand concentration of the metal ions in the anolyte of the one or moreelectrochemical cells;

instructions executable to acquire voltage for each one ofelectrochemical cells in an electrolyzer during operation;

instructions executable to acquire data related to the factorscomprising the current density and the concentration of the metal ionsin the anolyte during the operation of the one or more electrochemicalcells;

instructions executable to compare the acquired voltage with thecharacterized reference voltage range based on the factors; and

instructions executable to trigger an alarm when the acquired voltagedeviates from the reference voltage range.

In some embodiments of the above noted aspect, the instructionsexecutable to trigger the alarm comprise triggering the alarm by soundor otherwise, generating interlock protocol, generating shut-downprotocol, or combinations thereof.

In some embodiments of the above noted aspect and embodiment, computerprogram product further comprises, based on the comparison, instructionsexecutable to classify the cells as significantly damaged cells, damagedcells, and undamaged cells.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to storeinformation comprising the reference voltage range for each one of thecells; the acquired voltage for each one of the cells; the concentrationof the metal ions in the anolyte of the one or more electrochemicalcells; the concentration of salt ions in the anolyte of the one or moreelectrochemical cells; current density; and the comparison data.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to obtaininformation from one or more sensors adapted for measuring a physicalparameter of each one of the cells classified as significantly damagedcells or damaged cells, wherein the physical parameter comprises currentdistribution, coloration of liquid exiting the cells, pressure of gas inthe cells, pressure or flow of liquid entering the cells, pressure orflow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to evaluateat least one of a position and size of a pinhole in a membrane; positionof blockage of the flow in the cell; position of a pinch in feed line;fouling of the membrane; construction of the cell; welded points in thecell; or combinations thereof, using the measured physical parameter foreach one of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, computerprogram product further comprises, instructions executable to transmit asignal representative of a maintenance action to be performed on any oneof the significantly damaged or damaged cells, the maintenance actionbeing based on the evaluation of the significantly damaged or damagedcells.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Various modifications of the invention inaddition to those described herein will become apparent to those skilledin the art from the foregoing description and accompanying figures. Suchmodifications fall within the scope of the appended claims. Efforts havebeen made to ensure accuracy with respect to numbers used (e.g. amounts,temperature, etc.) but some experimental errors and deviations should beaccounted for. Unless indicated otherwise, parts are parts by weight,molecular weight is weight average molecular weight, temperature is indegrees Centigrade, and pressure is at or near atmospheric.

EXAMPLES Example 1 Monitoring of the Condition of the ElectrochemicalCell

The system to monitor condition of the cells in an electrolyzer or agroup of electrolyzers is set up by characterizing and saving methodssuch as, setting up reference voltage range with respect to theconcentration of the metal ions and the salt ions in the anolyte,setting up current density, and setting up start-up, steady state, andshut-down procedures. Setting up of the temperature window arounddesired measurement temperature, setting up maximum temperatureequilibration time, setting up cleaning procedure, and setting upmeasurement procedure may also be done.

The system is set up by setting up the voltage ramp rates (up and down);the voltage dwell time; the voltage amplitude; the number of measurementcycles; and the time between consecutive measurement cycles (measurementrate).

The data analysis algorithm is modified and stored on the processorboard.

The measurement method is initiated. The voltage measurement dataacquisition rate is set up. When the polarization level of each cell haspassed at start-up of the electrolyzer, the voltage distribution of thecells can be established by steadily increasing the current density andtaking voltage measurements continuously or at predefined steps. The rawcurrent data is viewed on a graph. The raw data files are storedlocally. The system is calibrated and the calibration file is stored onthe processor.

The voltage is read at various sampling rates. The acquired voltage datais plotted vs. time and is compared to the reference voltage range basedon the concentration of the metal ions. The voltage data is storedlocally.

Example 2 Monitoring of the Condition of the Electrochemical Cell

An electrochemical cell was run using the procedure described inExample 1. A reference voltage range was set up based on the current andconcentration of the metal ions in the anolyte fed into the anodechamber. Voltage measurements were done continuously to determine thatthe acquired voltage was within the reference voltage range (as shown inFIG. 5).

1. A method for monitoring condition of one or more electrochemicalcells in an electrolyzer, the method comprising: characterizing areference voltage range for one or more electrochemical cells in anelectrolyzer during operation, wherein the one or more electrochemicalcells comprise an anode in contact with an anolyte comprising metalions, and wherein the reference voltage range is dynamic dependent onfactors comprising current density and concentration of the metal ionsin the anolyte of the one or more electrochemical cells; acquiring avoltage of the one or more electrochemical cells during the operation;comparing the acquired voltage with the reference voltage range based onthe factors; and generating an alarm trigger when the acquired voltagedeviates from the reference voltage range, thereby monitoring thecondition of the one or more electrochemical cells in the electrolyzer.2. The method of claim 1, further comprising determining theconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells and based on the determination, characterizing thereference voltage range for the one or more electrochemical cells. 3.The method of claim 2, comprising determining the concentration of themetal ions in the feed anolyte and/or exit anolyte from the one or moreof the electrochemical cells in the electrolyzer.
 4. The method of claim1, wherein the anolyte further comprises salt ions and the factorsfurther comprise concentration of the salt ions in the anolyte duringthe operation of the one or more electrochemical cells.
 5. The method ofclaim 4, wherein the salt ions are alkali metal salt ions or alkalineearth metal salt ions.
 6. The method of claim 1, wherein theconcentration of the metal ions in the anolyte comprises concentrationof the metal ions in the lower oxidation state, concentration of themetal ions in the higher oxidation state, ratio of the concentration ofthe metal ions in the lower oxidation state to the metal ions in thehigher oxidation state, or combinations thereof.
 7. The method of claim1, wherein the metal ion is copper (Cu).
 8. The method of claim 1,wherein the concentration of the metal ions comprises concentration ofCu(I), concentration of Cu(II), concentration of total Cu(I) and Cu(II),ratio of the concentration of Cu(I) to Cu(II), or combinations thereof.9. The method of claim 1, further comprising obtaining data from in-situor ex-situ analytical techniques and based on the data determining theconcentration of the metal ions and/or the concentration of the saltions in the anolyte during the operation.
 10. The method of claim 9,wherein the in-situ or ex-situ analytical techniques comprise coriolismeter, titration of the anolyte, inductively coupled plasma (ICP)technique, ultra-microelectrode (UME) technique, or combinationsthereof.
 11. The method of claim 1, wherein the operation comprisesstart-up, shut-down, steady state, transient state, or combinationsthereof.
 12. The method of claim 1, wherein generating the alarm triggercomprises generating an alarm to analyze the one or more electrochemicalcells in the electrolyzer; generating interlock protocol; generatingshut-down protocol; or combinations thereof.
 13. The method of claim 1,further comprising classifying the one or more electrochemical cells assignificantly damaged, damaged, or undamaged, based on the comparison orthe alarm trigger.
 14. The method of claim 13, further comprisingmeasuring a physical parameter of the one or more electrochemical cellsclassified as significantly damaged or damaged, wherein the physicalparameter comprises current distribution, coloration of liquid exitingthe cells, pressure of gas in the cells, pressure or flow of liquidentering the cells, pressure or flow of liquid exiting the cells, orcombinations thereof.
 15. The method of claim 14, further comprisingbased on the measurement, evaluating: size and position of a pinhole ina membrane in the cell; position of blockage of the flow in the cell;position of a pinch in feed line; fouling of the membrane; constructionof the cell; welded points in the cell; or combinations thereof.
 16. Themethod of claim 15, further comprising taking a maintenance action onthe one or more electrochemical cells based on the evaluation.
 17. Asystem for monitoring condition of one or more electrochemical cells inan electrolyzer, the system comprising: a voltage acquisition modulecoupled to each one of electrochemical cells or a group of theelectrochemical cells in an electrolyzer and adapted for characterizinga reference voltage range and for acquiring voltage for each one of theelectrochemical cells or the group of the electrochemical cells duringoperation, wherein each one of the electrochemical cells comprise ananode in contact with an anolyte comprising metal ions, and wherein thereference voltage range is dynamic dependent on factors comprisingcurrent density and concentration of the metal ions in the anolyte ofthe one or more electrochemical cells; a factor acquisition moduleadapted for acquiring data related to the factors comprising the currentdensity and the concentration of the metal ions in the anolyte of theone or more electrochemical cells; a comparison module coupled to thevoltage acquisition module and the factor acquisition module, thecomparison module adapted to compare the acquired voltage with thecharacterized reference voltage range based on the factors; and triggeran alarm when the acquired voltage deviates from the reference voltagerange.
 18. The system of claim 17, wherein the factor acquisition moduleis adapted to acquire data related to the factors comprising the currentdensity, concentration of the metal ions in the lower oxidation state,concentration of the metal ions in the higher oxidation state, ratio ofthe concentration of the metal ions in the lower oxidation state to themetal ions in the higher oxidation state, and/or concentration of thesalt ions.
 19. The system of claim 17, further comprising a damageevaluation module coupled to the comparison module, the damageevaluation module adapted to obtain information from one or more sensorsadapted for measuring a physical parameter of each one of the cellsclassified as significantly damaged cells or damaged cells, wherein thephysical parameter comprises current distribution, coloration of liquidexiting the cells, pressure of gas in the cells, pressure or flow ofliquid entering the cells, pressure or flow of liquid exiting the cells,or combinations thereof.
 20. A computer program product encoded on anon-transitory computer-readable medium, which when executed, causes acomputer to monitor condition of one or more electrochemical cells in anelectrolyzer, the computer program product comprising: instructionsexecutable to characterize reference voltage range for each one ofelectrochemical cells in an electrolyzer during operation, wherein eachone of the electrochemical cells comprise an anode in contact with ananolyte comprising metal ions, and wherein the reference voltage rangeis dynamic dependent on factors comprising current density andconcentration of the metal ions in the anolyte of the one or moreelectrochemical cells; instructions executable to acquire voltage foreach one of electrochemical cells in an electrolyzer during operation;instructions executable to acquire data related to the factorscomprising the current density and the concentration of the metal ionsin the anolyte during the operation of the one or more electrochemicalcells; instructions executable to compare the acquired voltage with thecharacterized reference voltage range based on the factors; andinstructions executable to trigger an alarm when the acquired voltagedeviates from the reference voltage range.
 21. The system of claim 17,wherein the comparison module is farther adapted to classify the cellsas significantly damaged cells, damaged cells, and undamaged cells,based on the comparison.
 22. The system of claim 17, wherein the voltageacquisition module comprises a current controlling module, the currentcontrolling module being adapted to control current in each one of thecells or group of cells at start-up, steady state, shut-down, and/ortransient state of the cells.
 23. The system of claim 19, wherein thedamage evaluation module is adapted for evaluating at least one of aposition and size of a pinhole in a membrane; position of blockage ofthe flow in the cell; position of a pinch in feed line; fouling of themembrane; construction of the cell; welded points in the cell; orcombinations thereof, using the measured physical parameter for each oneof the significantly damaged or damaged cells.
 24. The system of claim23, further comprising an electrolyzer maintenance module coupled to thedamage evaluation module and adapted to transmit a signal representativeof a maintenance action to be performed on any one of the significantlydamaged cells or damaged cells, the maintenance action being based onthe evaluation of the significantly damaged cells or damaged cells.